/*
 * Architecture-specific trap handling.
 *
 * Copyright (C) 1998-2003 Hewlett-Packard Co
 *	David Mosberger-Tang <davidm@hpl.hp.com>
 *
 * 05/12/00 grao <goutham.rao@intel.com> : added isr in siginfo for SIGFPE
 */

#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/tty.h>
#include <linux/vt_kern.h>		/* For unblank_screen() */

#include <asm/fpswa.h>
#include <asm/hardirq.h>
#include <asm/ia32.h>
#include <asm/intrinsics.h>
#include <asm/processor.h>
#include <asm/uaccess.h>

/*
 * fp_emulate() needs to be able to access and update all floating point registers.  Those
 * saved in pt_regs can be accessed through that structure, but those not saved, will be
 * accessed directly.  To make this work, we need to ensure that the compiler does not end
 * up using a preserved floating point register on its own.  The following achieves this
 * by declaring preserved registers that are not marked as "fixed" as global register
 * variables.
 */
#ifdef ASM_SUPPORTED
register double f2 asm ("f2"); register double f3 asm ("f3");
register double f4 asm ("f4"); register double f5 asm ("f5");

register long f16 asm ("f16"); register long f17 asm ("f17");
register long f18 asm ("f18"); register long f19 asm ("f19");
register long f20 asm ("f20"); register long f21 asm ("f21");
register long f22 asm ("f22"); register long f23 asm ("f23");

register double f24 asm ("f24"); register double f25 asm ("f25");
register double f26 asm ("f26"); register double f27 asm ("f27");
register double f28 asm ("f28"); register double f29 asm ("f29");
register double f30 asm ("f30"); register double f31 asm ("f31");
#endif

extern spinlock_t timerlist_lock;

static fpswa_interface_t *fpswa_interface;

void __init
trap_init (void)
{
	int major = 0, minor = 0;

	if (ia64_boot_param->fpswa) {
		/* FPSWA fixup: make the interface pointer a kernel virtual address: */
		fpswa_interface = __va(ia64_boot_param->fpswa);
		major = fpswa_interface->revision >> 16;
		minor = fpswa_interface->revision & 0xffff;
	}
	printk(KERN_INFO "fpswa interface at %lx (rev %d.%d)\n",
	       ia64_boot_param->fpswa, major, minor);
}

/*
 * Unlock any spinlocks which will prevent us from getting the message out (timerlist_lock
 * is acquired through the console unblank code)
 */
void
bust_spinlocks (int yes)
{
	int loglevel_save = console_loglevel;

	if (yes) {
		oops_in_progress = 1;
		return;
	}

#ifdef CONFIG_VT
	unblank_screen();
#endif
	oops_in_progress = 0;
	/*
	 * OK, the message is on the console.  Now we call printk() without
	 * oops_in_progress set so that printk will give klogd a poke.  Hold onto
	 * your hats...
	 */
	console_loglevel = 15;		/* NMI oopser may have shut the console up */
	printk(" ");
	console_loglevel = loglevel_save;
}

void
die (const char *str, struct pt_regs *regs, long err)
{
	static struct {
		spinlock_t lock;
		u32 lock_owner;
		int lock_owner_depth;
	} die = {
		.lock =			SPIN_LOCK_UNLOCKED,
		.lock_owner =		-1,
		.lock_owner_depth =	0
	};
	static int die_counter;

	if (die.lock_owner != smp_processor_id()) {
		console_verbose();
		spin_lock_irq(&die.lock);
		die.lock_owner = smp_processor_id();
		die.lock_owner_depth = 0;
		bust_spinlocks(1);
	}

	if (++die.lock_owner_depth < 3) {
		printk("%s[%d]: %s %ld [%d]\n",
			current->comm, current->pid, str, err, ++die_counter);
		show_regs(regs);
  	} else
		printk(KERN_ERR "Recursive die() failure, output suppressed\n");

	bust_spinlocks(0);
	die.lock_owner = -1;
	spin_unlock_irq(&die.lock);
  	do_exit(SIGSEGV);
}

void
die_if_kernel (char *str, struct pt_regs *regs, long err)
{
	if (!user_mode(regs))
		die(str, regs, err);
}

void
ia64_bad_break (unsigned long break_num, struct pt_regs *regs)
{
	siginfo_t siginfo;
	int sig, code;

	/* SIGILL, SIGFPE, SIGSEGV, and SIGBUS want these field initialized: */
	siginfo.si_addr = (void *) (regs->cr_iip + ia64_psr(regs)->ri);
	siginfo.si_imm = break_num;
	siginfo.si_flags = 0;		/* clear __ISR_VALID */
	siginfo.si_isr = 0;

	switch (break_num) {
	      case 0: /* unknown error (used by GCC for __builtin_abort()) */
		die_if_kernel("bugcheck!", regs, break_num);
		sig = SIGILL; code = ILL_ILLOPC;
		break;

	      case 1: /* integer divide by zero */
		sig = SIGFPE; code = FPE_INTDIV;
		break;

	      case 2: /* integer overflow */
		sig = SIGFPE; code = FPE_INTOVF;
		break;

	      case 3: /* range check/bounds check */
		sig = SIGFPE; code = FPE_FLTSUB;
		break;

	      case 4: /* null pointer dereference */
		sig = SIGSEGV; code = SEGV_MAPERR;
		break;

	      case 5: /* misaligned data */
		sig = SIGSEGV; code = BUS_ADRALN;
		break;

	      case 6: /* decimal overflow */
		sig = SIGFPE; code = __FPE_DECOVF;
		break;

	      case 7: /* decimal divide by zero */
		sig = SIGFPE; code = __FPE_DECDIV;
		break;

	      case 8: /* packed decimal error */
		sig = SIGFPE; code = __FPE_DECERR;
		break;

	      case 9: /* invalid ASCII digit */
		sig = SIGFPE; code = __FPE_INVASC;
		break;

	      case 10: /* invalid decimal digit */
		sig = SIGFPE; code = __FPE_INVDEC;
		break;

	      case 11: /* paragraph stack overflow */
		sig = SIGSEGV; code = __SEGV_PSTKOVF;
		break;

	      case 0x3f000 ... 0x3ffff:	/* bundle-update in progress */
		sig = SIGILL; code = __ILL_BNDMOD;
		break;

	      default:
		if (break_num < 0x40000 || break_num > 0x100000)
			die_if_kernel("Bad break", regs, break_num);

		if (break_num < 0x80000) {
			sig = SIGILL; code = __ILL_BREAK;
		} else {
			sig = SIGTRAP; code = TRAP_BRKPT;
		}
	}
	siginfo.si_signo = sig;
	siginfo.si_errno = 0;
	siginfo.si_code = code;
	force_sig_info(sig, &siginfo, current);
}

/*
 * Unimplemented system calls.  This is called only for stuff that
 * we're supposed to implement but haven't done so yet.  Everything
 * else goes to sys_ni_syscall.
 *
 * XXX Remove this for v2.6.1.
 */
asmlinkage long
ia64_ni_syscall (unsigned long arg0, unsigned long arg1, unsigned long arg2, unsigned long arg3,
		 unsigned long arg4, unsigned long arg5, unsigned long arg6, unsigned long arg7,
		 unsigned long stack)
{
	return -ENOSYS;
}

/*
 * disabled_fph_fault() is called when a user-level process attempts to access f32..f127
 * and it doesn't own the fp-high register partition.  When this happens, we save the
 * current fph partition in the task_struct of the fpu-owner (if necessary) and then load
 * the fp-high partition of the current task (if necessary).  Note that the kernel has
 * access to fph by the time we get here, as the IVT's "Disabled FP-Register" handler takes
 * care of clearing psr.dfh.
 */
static inline void
disabled_fph_fault (struct pt_regs *regs)
{
	struct ia64_psr *psr = ia64_psr(regs);

	/* first, grant user-level access to fph partition: */
	psr->dfh = 0;
#ifndef CONFIG_SMP
	{
		struct task_struct *fpu_owner
			= (struct task_struct *)ia64_get_kr(IA64_KR_FPU_OWNER);

		if (ia64_is_local_fpu_owner(current))
			return;

		if (fpu_owner)
			ia64_flush_fph(fpu_owner);
	}
#endif /* !CONFIG_SMP */
	ia64_set_local_fpu_owner(current);
	if ((current->thread.flags & IA64_THREAD_FPH_VALID) != 0) {
		__ia64_load_fpu(current->thread.fph);
		psr->mfh = 0;
	} else {
		__ia64_init_fpu();
		/*
		 * Set mfh because the state in thread.fph does not match the state in
		 * the fph partition.
		 */
		psr->mfh = 1;
	}
}

static inline int
fp_emulate (int fp_fault, void *bundle, long *ipsr, long *fpsr, long *isr, long *pr, long *ifs,
	    struct pt_regs *regs)
{
	fp_state_t fp_state;
	fpswa_ret_t ret;

	if (!fpswa_interface)
		return -1;

	memset(&fp_state, 0, sizeof(fp_state_t));

	/*
	 * compute fp_state.  only FP registers f6 - f11 are used by the
	 * kernel, so set those bits in the mask and set the low volatile
	 * pointer to point to these registers.
	 */
	fp_state.bitmask_low64 = 0xfc0;  /* bit6..bit11 */

	fp_state.fp_state_low_volatile = (fp_state_low_volatile_t *) &regs->f6;
	/*
	 * unsigned long (*EFI_FPSWA) (
	 *      unsigned long    trap_type,
	 *	void             *Bundle,
	 *	unsigned long    *pipsr,
	 *	unsigned long    *pfsr,
	 *	unsigned long    *pisr,
	 *	unsigned long    *ppreds,
	 *	unsigned long    *pifs,
	 *	void             *fp_state);
	 */
	ret = (*fpswa_interface->fpswa)((unsigned long) fp_fault, bundle,
					(unsigned long *) ipsr, (unsigned long *) fpsr,
					(unsigned long *) isr, (unsigned long *) pr,
					(unsigned long *) ifs, &fp_state);

	return ret.status;
}

/*
 * Handle floating-point assist faults and traps.
 */
static int
handle_fpu_swa (int fp_fault, struct pt_regs *regs, unsigned long isr)
{
	long exception, bundle[2];
	unsigned long fault_ip;
	struct siginfo siginfo;
	static int fpu_swa_count = 0;
	static unsigned long last_time;

	fault_ip = regs->cr_iip;
	if (!fp_fault && (ia64_psr(regs)->ri == 0))
		fault_ip -= 16;
	if (copy_from_user(bundle, (void *) fault_ip, sizeof(bundle)))
		return -1;

	if (jiffies - last_time > 5*HZ)
		fpu_swa_count = 0;
	if ((fpu_swa_count < 4) && !(current->thread.flags & IA64_THREAD_FPEMU_NOPRINT)) {
		last_time = jiffies;
		++fpu_swa_count;
		printk(KERN_WARNING
		       "%s(%d): floating-point assist fault at ip %016lx, isr %016lx\n",
		       current->comm, current->pid, regs->cr_iip + ia64_psr(regs)->ri, isr);
	}

	exception = fp_emulate(fp_fault, bundle, &regs->cr_ipsr, &regs->ar_fpsr, &isr, &regs->pr,
			       &regs->cr_ifs, regs);
	if (fp_fault) {
		if (exception == 0) {
			/* emulation was successful */
			ia64_increment_ip(regs);
		} else if (exception == -1) {
			printk(KERN_ERR "handle_fpu_swa: fp_emulate() returned -1\n");
			return -1;
		} else {
			/* is next instruction a trap? */
			if (exception & 2) {
				ia64_increment_ip(regs);
			}
			siginfo.si_signo = SIGFPE;
			siginfo.si_errno = 0;
			siginfo.si_code = __SI_FAULT;	/* default code */
			siginfo.si_addr = (void *) (regs->cr_iip + ia64_psr(regs)->ri);
			if (isr & 0x11) {
				siginfo.si_code = FPE_FLTINV;
			} else if (isr & 0x22) {
				/* denormal operand gets the same si_code as underflow 
				* see arch/i386/kernel/traps.c:math_error()  */
				siginfo.si_code = FPE_FLTUND;
			} else if (isr & 0x44) {
				siginfo.si_code = FPE_FLTDIV;
			}
			siginfo.si_isr = isr;
			siginfo.si_flags = __ISR_VALID;
			siginfo.si_imm = 0;
			force_sig_info(SIGFPE, &siginfo, current);
		}
	} else {
		if (exception == -1) {
			printk(KERN_ERR "handle_fpu_swa: fp_emulate() returned -1\n");
			return -1;
		} else if (exception != 0) {
			/* raise exception */
			siginfo.si_signo = SIGFPE;
			siginfo.si_errno = 0;
			siginfo.si_code = __SI_FAULT;	/* default code */
			siginfo.si_addr = (void *) (regs->cr_iip + ia64_psr(regs)->ri);
			if (isr & 0x880) {
				siginfo.si_code = FPE_FLTOVF;
			} else if (isr & 0x1100) {
				siginfo.si_code = FPE_FLTUND;
			} else if (isr & 0x2200) {
				siginfo.si_code = FPE_FLTRES;
			}
			siginfo.si_isr = isr;
			siginfo.si_flags = __ISR_VALID;
			siginfo.si_imm = 0;
			force_sig_info(SIGFPE, &siginfo, current);
		}
	}
	return 0;
}

struct illegal_op_return {
	unsigned long fkt, arg1, arg2, arg3;
};

struct illegal_op_return
ia64_illegal_op_fault (unsigned long ec, unsigned long arg1, unsigned long arg2,
		       unsigned long arg3, unsigned long arg4, unsigned long arg5,
		       unsigned long arg6, unsigned long arg7, unsigned long stack)
{
	struct pt_regs *regs = (struct pt_regs *) &stack;
	struct illegal_op_return rv;
	struct siginfo si;
	char buf[128];

#ifdef CONFIG_IA64_BRL_EMU
	{
		extern struct illegal_op_return ia64_emulate_brl (struct pt_regs *, unsigned long);

		rv = ia64_emulate_brl(regs, ec);
		if (rv.fkt != (unsigned long) -1)
			return rv;
	}
#endif

	sprintf(buf, "IA-64 Illegal operation fault");
	die_if_kernel(buf, regs, 0);

	memset(&si, 0, sizeof(si));
	si.si_signo = SIGILL;
	si.si_code = ILL_ILLOPC;
	si.si_addr = (void *) (regs->cr_iip + ia64_psr(regs)->ri);
	force_sig_info(SIGILL, &si, current);
	rv.fkt = 0;
	return rv;
}

void
ia64_fault (unsigned long vector, unsigned long isr, unsigned long ifa,
	    unsigned long iim, unsigned long itir, unsigned long arg5,
	    unsigned long arg6, unsigned long arg7, unsigned long stack)
{
	struct pt_regs *regs = (struct pt_regs *) &stack;
	unsigned long code, error = isr;
	struct siginfo siginfo;
	char buf[128];
	int result, sig;
	static const char *reason[] = {
		"IA-64 Illegal Operation fault",
		"IA-64 Privileged Operation fault",
		"IA-64 Privileged Register fault",
		"IA-64 Reserved Register/Field fault",
		"Disabled Instruction Set Transition fault",
		"Unknown fault 5", "Unknown fault 6", "Unknown fault 7", "Illegal Hazard fault",
		"Unknown fault 9", "Unknown fault 10", "Unknown fault 11", "Unknown fault 12",
		"Unknown fault 13", "Unknown fault 14", "Unknown fault 15"
	};

	if ((isr & IA64_ISR_NA) && ((isr & IA64_ISR_CODE_MASK) == IA64_ISR_CODE_LFETCH)) {
		/*
		 * This fault was due to lfetch.fault, set "ed" bit in the psr to cancel
		 * the lfetch.
		 */
		ia64_psr(regs)->ed = 1;
		return;
	}

	switch (vector) {
	      case 24: /* General Exception */
		code = (isr >> 4) & 0xf;
		sprintf(buf, "General Exception: %s%s", reason[code],
			(code == 3) ? ((isr & (1UL << 37))
				       ? " (RSE access)" : " (data access)") : "");
		if (code == 8) {
# ifdef CONFIG_IA64_PRINT_HAZARDS
			printk("%s[%d]: possible hazard @ ip=%016lx (pr = %016lx)\n",
			       current->comm, current->pid, regs->cr_iip + ia64_psr(regs)->ri,
			       regs->pr);
# endif
			return;
		}
		break;

	      case 25: /* Disabled FP-Register */
		if (isr & 2) {
			disabled_fph_fault(regs);
			return;
		}
		sprintf(buf, "Disabled FPL fault---not supposed to happen!");
		break;

	      case 26: /* NaT Consumption */
		if (user_mode(regs)) {
			void *addr;

			if (((isr >> 4) & 0xf) == 2) {
				/* NaT page consumption */
				sig = SIGSEGV;
				code = SEGV_ACCERR;
				addr = (void *) ifa;
			} else {
				/* register NaT consumption */
				sig = SIGILL;
				code = ILL_ILLOPN;
				addr = (void *) (regs->cr_iip + ia64_psr(regs)->ri);
			}
			siginfo.si_signo = sig;
			siginfo.si_code = code;
			siginfo.si_errno = 0;
			siginfo.si_addr = addr;
			siginfo.si_imm = vector;
			siginfo.si_flags = __ISR_VALID;
			siginfo.si_isr = isr;
			force_sig_info(sig, &siginfo, current);
			return;
		} else if (done_with_exception(regs))
			return;
		sprintf(buf, "NaT consumption");
		break;

	      case 31: /* Unsupported Data Reference */
		if (user_mode(regs)) {
			siginfo.si_signo = SIGILL;
			siginfo.si_code = ILL_ILLOPN;
			siginfo.si_errno = 0;
			siginfo.si_addr = (void *) (regs->cr_iip + ia64_psr(regs)->ri);
			siginfo.si_imm = vector;
			siginfo.si_flags = __ISR_VALID;
			siginfo.si_isr = isr;
			force_sig_info(SIGILL, &siginfo, current);
			return;
		}
		sprintf(buf, "Unsupported data reference");
		break;

	      case 29: /* Debug */
	      case 35: /* Taken Branch Trap */
	      case 36: /* Single Step Trap */
		if (fsys_mode(current, regs)) {
			extern char __kernel_syscall_via_break[];
			/*
			 * Got a trap in fsys-mode: Taken Branch Trap and Single Step trap
			 * need special handling; Debug trap is not supposed to happen.
			 */
			if (unlikely(vector == 29)) {
				die("Got debug trap in fsys-mode---not supposed to happen!",
				    regs, 0);
				return;
			}
			/* re-do the system call via break 0x100000: */
			regs->cr_iip = (unsigned long) __kernel_syscall_via_break;
			ia64_psr(regs)->ri = 0;
			ia64_psr(regs)->cpl = 3;
			return;
		}
		switch (vector) {
		      case 29:
			siginfo.si_code = TRAP_HWBKPT;
#ifdef CONFIG_ITANIUM
			/*
			 * Erratum 10 (IFA may contain incorrect address) now has
			 * "NoFix" status.  There are no plans for fixing this.
			 */
			if (ia64_psr(regs)->is == 0)
			  ifa = regs->cr_iip;
#endif
			break;
		      case 35: siginfo.si_code = TRAP_BRANCH; ifa = 0; break;
		      case 36: siginfo.si_code = TRAP_TRACE; ifa = 0; break;
		}
		siginfo.si_signo = SIGTRAP;
		siginfo.si_errno = 0;
		siginfo.si_addr  = (void *) ifa;
		siginfo.si_imm   = 0;
		siginfo.si_flags = __ISR_VALID;
		siginfo.si_isr   = isr;
		force_sig_info(SIGTRAP, &siginfo, current);
		return;

	      case 32: /* fp fault */
	      case 33: /* fp trap */
		result = handle_fpu_swa((vector == 32) ? 1 : 0, regs, isr);
		if ((result < 0) || (current->thread.flags & IA64_THREAD_FPEMU_SIGFPE)) {
			siginfo.si_signo = SIGFPE;
			siginfo.si_errno = 0;
			siginfo.si_code = FPE_FLTINV;
			siginfo.si_addr = (void *) (regs->cr_iip + ia64_psr(regs)->ri);
			siginfo.si_flags = __ISR_VALID;
			siginfo.si_isr = isr;
			siginfo.si_imm = 0;
			force_sig_info(SIGFPE, &siginfo, current);
		}
		return;

	      case 34:
		if (isr & 0x2) {
			/* Lower-Privilege Transfer Trap */
			/*
			 * Just clear PSR.lp and then return immediately: all the
			 * interesting work (e.g., signal delivery is done in the kernel
			 * exit path).
			 */
			ia64_psr(regs)->lp = 0;
			return;
		} else {
			/* Unimplemented Instr. Address Trap */
			if (user_mode(regs)) {
				siginfo.si_signo = SIGILL;
				siginfo.si_code = ILL_BADIADDR;
				siginfo.si_errno = 0;
				siginfo.si_flags = 0;
				siginfo.si_isr = 0;
				siginfo.si_imm = 0;
				siginfo.si_addr = (void *) (regs->cr_iip + ia64_psr(regs)->ri);
				force_sig_info(SIGILL, &siginfo, current);
				return;
			}
			sprintf(buf, "Unimplemented Instruction Address fault");
		}
		break;

	      case 45:
#ifdef CONFIG_IA32_SUPPORT
		if (ia32_exception(regs, isr) == 0)
			return;
#endif
		printk(KERN_ERR "Unexpected IA-32 exception (Trap 45)\n");
		printk(KERN_ERR "  iip - 0x%lx, ifa - 0x%lx, isr - 0x%lx\n",
		       regs->cr_iip, ifa, isr);
		force_sig(SIGSEGV, current);
		break;

	      case 46:
#ifdef CONFIG_IA32_SUPPORT
		if (ia32_intercept(regs, isr) == 0)
			return;
#endif
		printk(KERN_ERR "Unexpected IA-32 intercept trap (Trap 46)\n");
		printk(KERN_ERR "  iip - 0x%lx, ifa - 0x%lx, isr - 0x%lx, iim - 0x%lx\n",
		       regs->cr_iip, ifa, isr, iim);
		force_sig(SIGSEGV, current);
		return;

	      case 47:
		sprintf(buf, "IA-32 Interruption Fault (int 0x%lx)", isr >> 16);
		break;

	      default:
		sprintf(buf, "Fault %lu", vector);
		break;
	}
	die_if_kernel(buf, regs, error);
	force_sig(SIGILL, current);
}
